A. S. Serdyuk, “Approximation of Periodic Analytic Functions by Interpolation Trigonometric Polynomials in the Metric of the Space $L$”, Ukr. Mat. Zhurn., vol. 54, no. 5, pp. 692–699, May 2002, Accessed: Apr. 13, 2025. [Online]. Available: https://umj.imath.kiev.ua/index.php/umj/article/view/4108